The overall goal of the Population Sciences (PS) Program is to reduce and prevent morbidity and mortality associated with cancer and its treatment, particularly cancer-related problems that are important to the community that we serve. We strive to attain these goals through primary and secondary prevention, using epidemiology and molecular approaches to identify risk factors for cancer and to make targeted efforts to reduce exposure to these agents, particularly among populations who are most at risk. Because tobacco smoke exposure is responsible for a large portion of the cancer burden, and use is high in our catchment area, many of our efforts are targeted at reducing use of tobacco through a number of approaches. Our research also focuses on tertiary prevention, to understand factors that may impact treatment outcomes, and to design interventions to improve prognosis. To address these goals for primary, secondary and tertiary prevention, our research is driven by three specific aims. 1) To reduce the burden of smoking-related cancers by preventing exposure to tobacco and tobacco products, with research focused at the individual, regional, national and global levels; 2) using molecular epidemiology, to understand who is at high risk of cancer from exposures and susceptibility, and to elucidate underlying biologic pathways of carcinogenesis, to inform prevention and early detection strategies; and 3) to investigate factors that influence cancer treatment outcomes, to enhance quality of life and improve survival. The PS program is co-led by Drs. Christine Ambrosone and Andrew Hyland, who have complementary expertise that bridges these aims. Together, they facilitate research in discovery, to identify genetic and environmental causes of cancer and its outcomes as well as approaches to prevention, reducing exposure to etiologic factors and devising interventions to reduce risk and improve cancer survival. In addition to a large portfolio of research in molecular epidemiology, disparities and tobacco control, highlights in the last funding period included P01-and R01-funded intra- and inter-programmatic research on the etiology of aggressive breast cancer in African-American women, with findings leading to interventions in the community led by members of the Community Outreach and Engagement Office, and leadership of the largest longitudinal study of tobacco use and health outcomes ever conducted, the Path Study, including more than 45,000 participants, which will inform FDA regulatory science. The 25 members of the PS Program have $4.1M in total peer reviewed funding, of which $2.9M is from NCI. Of the 521 publications since 2013, 47 (9%) were published in journals with impact factor > 10, with 113 (22%) inter programmatic, 112 (21%) intra programmatic, and 487 (93%) collaborative with investigators at other institutions. In the coming cycle, PS members will continue to build upon their strengths, and to expand into areas where there are current gaps, with a goal to reduce cancer morbidity and mortality, particularly in our catchment area.